Abrasive paper retaining clip



0d. 8, 1968 THOMAS 3,404,493

ABRASIVE PAPER RETAINING CLIP Filed Sept. 2, 1966 5a Fig.4 I 64 b #33840 Eugene E. Thomas INVENTOR.

United States Patent ABSTRACT OF THE DISCLOSURE A sanding shoe having alower jaw and an upper jaw at one end thereof for releasably clamping anend of an abrasive sheet therebetween. An over-center type actuator isattached to the upper jaw for lifting the upper jaw away from the lowerjaw to release the abrasive sheet and to enable clamping of anotherabrasive sheet. The upper jaw includes a depending lip having serrationsor teeth formed thereon while the lower jaw includes an upturned lip togrippingly engage the end of the abrasive sheet. The actuator for theupper jaw is releasably retained in its jaw-opening position and in itsjaw-closing position with an offset end portion thereof riding againstan extension on the lower jaw during its pivotal movement and alsoengaging the terminal end of the abrasive sheet to force it against theinner surface of the lip on the upper jaw when the actuator is in thejaw-closing position.

The present invention generally relates to a retaining clip or holdingdevice for abrasive paper such as that employed in conjunction withreciprocating and oscillating sanding machines for the purpose ofsecuring a sheet of abrasive material to the sanding shoe which isoperated by the sanding machine.

An object of the present invention is to provide a retaining clip forabrasive paper such as sandpaper or the like to the oscillating orreciprocating shoe or plate of a sanding machine which enables theabrasive sheet to be easily attached to the sanding shoe and easilyremoved therefrom for replacement.

Another object of the present invention is to provide an abrasive papersheet retaining clip which is easy to operate and yet relatively simpleand inexpensive to manufacture and which serves to securely retain theabrasive sheet in position on the oscillating and reciprocatingsandingshoe.

A further object of the present invention is to provide a retaining clipin accordance with the preceding objects for enabling replacement andeasy attachment of a sandpaper sheet or the like to a sanding shoe inwhich the retaining clip has an actuator operable to render a clampingjaw inoperative with the actuator having an overcenter position toretain the clamping jaw in inoperative position until such time as theretaining clip is manually operated to the position for retaining thesanding or abrasive sheet in clamped position by permitting the clampingjaw to return to its operative position.

A still further object of this invention is to provide a retaining clipassembly in which a lower clip which is constructed to lift the end ofthe sanding shoe upwardly while the upper clip is pressing downwardlyagainst the abrasive sheet at the same time is mounted on the shoethereby neutralizing the spring pressure on the end of the sanding shoe.

Still another important feature of the present invention is to provide aretaining clip for an abrasive sheet which includes a spring-biasedgripping jaw structure together with an actuating handle pivotallyattached to the jaw structure and including an offset portion whichswings about a horizontal axis for engaging a portion of the sandingshoe so that upward force may be exerted on the gripping jaw forreleasing the' gripping jaw from its clamped or operative position andalso forms a double lock for the abrasive sheet by virtue of the offsetportion of the actuating member reversely bending the sheet behind theupper gripping jaw.

' These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accomq panying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIGURE 1 is a top plan view of a sander employing the retaining clip ofthe present invention;

FIGURE 2 is an enlarged plan view of one end of the sanding deviceillustrating in more detail the structure of the retaining clip at eachend of the sander;

FIGURE 3 is an end view of the construction of FIG- URE 2 with portionsthereof broken away illustrating the structural details of theinvention;

FIGURE 4 is a side elevational view of the construction of FIGURE 2illustrating the retaining clip in operative position;

FIGURE 5 is a sectional view taken substantially upon a plane passingalong section line 55 of FIGURE 2 illustrating the retaining clip inreleased position with the actuating lever in its over-center positionand engaged with a detent therefor and also illustrating the lower clipin dashed line prior to attachment to the shoe.

Referring now specifically to the drawings, the numeral generallydesignates the retaining clip of the present invention with there beinga similar clip at each end of a sander 12. The sander 12 may be poweroperated or manually operated and includes a sanding shoe or plate 14which is oscillated or reciprocated by a handle 16 or in the case of asanding machine, the sanding shoe 14 is oscillated or reciprocated alongits longitudinal axis by a connection with a pneumatic or hydraulicpower device or an electric power device of any suitable construction.The sanding shoe 14 includes a resilient pad 18 bonded thereto andforming a backing for an abrasive sheet 20 such as sandpaper, emerypaper or the like. Each end of the sanding shoe or plate 14 is slightlyupwardly curved as at 22 and this is also true of the sanding pad 24thus forming an end for the sanding shoe and pad which is upwardlycurved for engagement with the end portion 26 of the abrasive sheet 20.

Attached to the upper surface of the sanding shoe or plate 14 is agenerally Ushaped lower jaw 28 having a pair of legs 30 and 32 which areinterconnected at their forward ends by a transverse bight portion 34having an upturned free edge 36 which lies against the upper surface ofthe upturned end portion 22 of the plate 14 as illustrated in FIGURE 5.The bight portion of the lower jaw is provided with a rearwardlyextending projection 38 centrally disposed thereon which terminates inan upturned end 40 which forms an abutment for a purpose describedhereinafter. The legs 30' and 32 are secured to the shoe or plate 14 bya plurality of fasteners 42, 44 and 46 with the fasteners 46 alsosecuring an upper jaw generally designated by numeral 48 to the plate 14by virtue of the fasteners 46 extending through legs 50 and 52 of thegenerally Ushaped upper jaw '48 that is constructed of spring metal andincludes a forward transverse bight portion 54 interconnecting the legs50 and 52 with the bight portion terminating in a downturned edge or lip56 having teeth or serrations 58 formed in the lower edge thereof forsecurely gripping the end of the abrasive sheet 2-6 between the upturnedend portion 36 of the lower jaw and the serrated or toothed edge 58 ofthe downturned lip 56 of the upper jaw 48. The operative position of theupper jaw is illustrated in FIGURE 4 and the inoperative position isillustrated in FIGURES 3 and S. An actuator generally designated bynumeral 60 is provided for moving the upper jaw 48 to the inoperativeposition against the inherent resiliency of the upper jaw 48. Theactuator includes an elongated wire rod 62 having a finger loop 64formed on the free end thereof and with the other end having an offsetportion 66 and a laterally extending portion 68 that is journalled, forpivotal movement about a transverse axis, in the pair of downturned lugsor ears 70 formed on the side edges of ar'e'arward extension 72 formedon the bight portion 58. The portion of the rearward extension 72adjacent each of the lugs 70 is provided with a longitudinal rib 74formed therein for rigidifying and reinforcing this portion of the upperjaw 48. The laterally extending terminal end of the actuator 60 isjournalled in the spaced lugs 70 with the portion of the end 68 disposedbetween the lugs 70 being generally semi-circular or U-shaped in"configuration and offset in the manner illustrated in FIGURES 2 and 3with this offset portion being designated by numeral 76 and serving as alift member when engaged with the upper surface of the rearwardlyextending extension 38 on the lower jaw 28 with the blight portion ofthe offset portion 7-6 engaging the upstanding abutment 80 after theelongated portion of the handle 62 has gone past center thus forming anover-center position so that the upper jaw 48 will be retained in itsopen or inoperative position.

A latching element 78 is provided on the leg 32 of the lower jaw 28forming an inwardly opening lug under which the wire rod handle 62forming part of the actuator may be positioned by inwardly flexing thewire rod handle 62 when it is moved downwardly toward the plate 14so'that it may be moved under the inwardly extending lug which forms thetop end of the latching element 78 thus retaining the actuator 60 moreor less parallel with the shoe or plate 14 so that the resilient sheetmetal from which the upper jaw is formed will urge the clamping teeth orserrations 58 into secure locking engagement with the end 26 of theabrasive sheet 20 to securely clamp it in position against the upwardlycurved end portion 34 and the terminal edge 36 of the lower jaw 28 asillustrated in FIGURE 4. When it is desired to release the abrasivesheet of paper, the loop 64 is grasped and moved laterally inwardly andthen upwardly so that the actuator will fulcrum about an axis defined bythe end portion 68 thus bringing the U-shaped offset portion 76 ofactuator '60 into engagement with the upper surface of the lower jaw sothat it will move rearwardly toward the abutment 70 thus elevating thegripping teeth 58 to inoperative position.

The rubber pad 18 may be of any conventional high density live rubberbonded to the shoe or plate 14 which is preferably made of magnesium oran equivalent material for minimum weight and maximum strength. Rivetsor other suitable fasteners may be employed for securing the upper andlower jaws in position on the shoe. As illustrated in FIGURE 4, theportion of the abrasive sheet which goes over the end portion 36 of thelower jaw actually forms one curve in the abrasive sheet and where theabrasive sheet goes under the clamping teeth 58 of the upper jaw, thereis a second curve formed in the abrasive sheet thus providing a positivegripping action which will prevent slippage. The teeth 58 actually mashthe abrasive sheet against the inner surface of the upturned end portion36 of the lower jaw thus forming another curve in the abrasive sheet.The teeth not only prevent longitudinal slippage but also prevent sideslippage even when severe forward or side movements are applied with arelatively powerful sanding machine. Locking of the operating rod 62prevents rattle and excessive wear to the equipment. The over-centerposition of the actuating mechanism will prevent any possible injury tothe fingers while loading the abrasive sheet. To prevent any possibleaccidental closing of the jaw 48, the rearward extension 38 is providedwith a small upwardly extending hump or detent 80 to positively lock theactuator 4 60 in position for retaining the upper jaw spaced from thelower jaw. Also, the dimensional characteristics of the actuator aresuch as to force the upper jaw a substantial distance away from thelower jaw to facilitate loading of abrasive sheets therein.

The bottom jaw 28 is constructed of resilient sheet metal and, asillustrated in dashed line in FIG. 5, is normally formed with thecentral portion slightly lower than the end portions so that the outerend portion is normally upwardly inclined before it is secured to theshoe 14 by the fasteners 42. This will exert an upward force on the shoe14 due to the tendency of the forward end of the lower jaw 28 to returnto its normal position. This upward force exerted on the shoe willcounteract the downward force exerted by the upper jaw thus eliminatingany tendency of the shoe to be deflected downwardly by the grippingaction of the upper jaw.

As illustrated in FIG. 4, the rounded end of offset portion 76 actuallyslides along the surface of rearward extension 38 and will catch thefree end of the abrasive sheet and fold it upwardly toward the innersurface of the lip 56. Due to the positive inclination of edge 36 of thelower jaw 28 and the reverse break in the abrasive sheet formed byoffset portion 76 and teeth 58 and the holding of the sheet against therear surface of lip 56, a positive retaining action is provided for theabrasive sheet.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. In a sander having a generally planar shoe for receiving an abrasivesheet, means for operating said shoe, an upper jaw and a lower jawattached to one end of said shoe with the upper jaw being movable inrelation to the lower jaw and being spring-biased toward the lower jawfor gripping an end of an abrasive sheet therebetween, an actuatorattached to the upper jaw for swinging movement in relation theretoabout a transverse axis and including an actuating element offset fromthe transverse axis for lifting the upper jaw away from the lower jaw torelease an abrasive sheet and enable the end of another abrasive sheetto be inserted therebetween, said upper jaw terminating in a dependinglip having serrations in the lower edge thereof forming gripping teeth,said lower jaw being provided with an upwardly curved upper surfaceterminating in an edge portion spaced longitudinally from the grippingteeth whereby an abrasive sheet gripped between the gripping teeth andthe lower jaw will be caused to curve around the edge of the lower jawand be gripped by the gripping teeth, said actuator including a wire rodhandle having a loop on the end thereof, a catch mechanism associatedwith the wire rod handle for retaining the actuator in operativeposition for enabling the upper jaw to grip the abrasive sheet, saidlower jaw being provided with a rearward extension engaged by the offsetactuating element and including an upturned abutment at the inner edgethereof for engagement by the actuating element when the actuator is inan over-center position beyond the vertical.

2. The structure as defined in claim 1 wherein said actuator element isprovided with a rounded actuating surface oriented centrally of saidshoe for engaging, the lower jaw over a relatively minor surface area toreduce the force nesessary to move the actuator from its operative toinoperative position and from inoperative to operative position.

3. The structure as defined in claim 2 wherein said upper jaw includes arearward extension having downturned lugs pivotally receiving saidactuator, said extension including reinforcing ribs formed thereon forrigidifying the extension.

4. An abrasive sheet retaining clip assembly for use in combination witha sanding shoe comprising a lower jaw and an upper jaw, the lower jawadapted to be secured to the sanding shoe, the upper jaw overlying thelower jaw with the inner end thereof rigid with respect to the lower jawand the outer end being movable in relation to the lower jaw forselectively gripping the abrasive sheet, said jaws being constructed ofspring metal, the outer end of the lower jaw being deformed downwardlywhen secured to the shoe for exerting an upward force thereon forcounteracting the downward force exerted by the free end of the upperjaw when gripping the abrasive sheet.

5. An abrasive sheet retaining clip assembly for use in combination witha sanding shoe comprising a lower jaw and an upper jaw, the lower jawadapted to be secured to the sanding shoe, the upper jaw overlying thelower jaw with the inner end thereof rigid with respect to the lower jawand the outer end being movable in relation to the lower jaw forselectively gripping the abrasive sheet, said jaws being constructed ofspring metal, the free ends of said jaws having angularly extending lipsdisposed in overlapping relation to form a plurality of reverse curvesin the abrasive sheet, an actuator pivotally supported on the upper jawand including a handle portion for operation thereof and an offsetportion engaging the upper surface of the lower jaw to move the upperjaw away from the lower jaw when the actuator is pivoted in onedirection toward a jaw opening position, and means on the lower jaw forreleasably locking the actuator in jaw opening position, said lockingmeans including a pair of upwardly extending projections formed on thelower jaw in closely spaced relation to receive the offset portion whenin jaw opening position.

6. An abrasive sheet retaining clip assembly for use in combination witha sanding shoe comprising a lower jaw and an upper jaw, the lower jawadapted to be secured to the sanding shoe, the upper jaw overlying thelower jaw with the inner end thereof rigid with respect to the lower jawand the outer end being movable in relation to the lower jaw forselectively gripping the abrasive sheet, said jaws being constructed ofspring metal, the free ends of said jaws having angularly extending lipsdisposed in overlapping relation to form a plurality of reverse curvesin the abrasive sheet, an actuator pivotally supported on the upper jawand including a handle portion for operation thereof and an offsetportion engaging the upper surface of the lower jaw to move the upperjaw away from the lower jaw when the actuator is pivoted in onedirection toward a jaw opening position, and means on the lower jaw forreleasably locking the actuator in jaw opening position, and a latchmeans engaged with said handle portion to retain the actuator in jawclosing position.

7. The structure as defined in claim 6 wherein said offset portion isdimensioned to be oriented adjacent the inner surface of the lip on theupper jaw when the actuator is in jaw closing position for clamping theabrasive sheet against the inner surface of the lip on the upper jaw.

References Cited UNITED STATES PATENTS 2,282,043 5/ 1942 Ekstrom 5-l-3842,402,069 6/ 1946 Minnick 51-382 2,481,309 9/ 1949 Gunnarson 51382 X2,683,337 7/1954 Scace 51-684 3,183,638 5/1965 Hutchins 51-386 3,267,6228/1966 Frostad 51-384 ROBERT C. RIORDON, Primary Examiner.

D. G. KELLY, Assistant Examiner.

